This application relates to and incorporates herein by reference Japanese Patent Application No. 11-286828 filed on Oct. 7, 1999.
The present invention relates to a wireless communication method which uses an on-board apparatus communicating with outside in a short range wireless communication system.
There has conventionally been known VICS (Vehicle Information and Communication System) as one of systems providing various services to a user of a vehicle by carrying out wireless communication between an on-board apparatus mounted on the vehicle and a fixed station installed outside of the vehicle for conveying to a driver, for example, road traffic information on congestion of road, vacancy of a parking lot or the like to improve traffic flow or to achieve pertinent guidance to the parking lot.
According to VICS, there is used radio wave beacon for carrying out one-way communication of an announcing type or optical beacon capable of carrying out two-way communication for providing information within a narrow or limited area.
However, in the case of radio wave beacon, owing to the one-way communication of the announcing type, communication cannot be carried out from the on-board apparatus to the fixed station. Meanwhile, in the case of optical beacon, although the two-way communication can be carried out, the optical beacon is not available to general users. Therefore, according to VICS, services of sophisticated function for general users utilizing the two-way communication cannot be realized.
In contrast thereto, there is known ATIS (Advanced Traffic Information Service) capable of carrying out the two-way communication. It utilizes a mobile communication apparatus such as a portable telephone, a car telephone or the like. However, according to ATIS, information is transmitted via a public communication network and accordingly, the transmission capacity is about 64 kbps. Thus, much time is taken for transmitting a large amount of data such as image or the like. Further, according to ATIS, information is controlled concentratedly at a center (fixed station) and accordingly, the center needs to deal with information over a wide range and cannot deal with extremely local and instantaneous information such as, for example, a behavior of an individual vehicle constituting effective information in view of promoting safety of running or the like.
Further, in wireless communication between an on-board apparatus and a fixed station, it is expected to realize personal communication with respect to a specific vehicle (on-board apparatus) accompanied by settling charge or the like. However, according to radio wave beacon of VICS, despite the limited area, a communication area is as large as about 70 m, a plurality of vehicles can enter to the same area and accordingly, there is a high possibility of receiving communication by an on-board apparatus of other unrelated vehicle. It is difficult to apply the radio wave beacon of VICS to a use requesting such a high individuality.
Hence, it is an object of the invention to provide an improved a short range wireless communication method.
According to the present invention, the method is implemented by using a short range wireless communication between an on-board apparatus mounted on a vehicle and an outside such as a fixed station. In this communication, millimetric wave of, for instance, 5.8 GHz is used, thus limiting the communication area to 3 meters to 30 meters. The power of millimetric wave attenuates very progressively as the transmission distance increases.
This communication method is applicable to a system in which a service is requested from a vehicle and a service charge is required, a vehicle history information is provided at a car repair shop, a warning of an opposing vehicle is provided at an invisible corner, or the like.